B1

• Differentiation is the process by which cells become specialised for a job
• The cells that differentiate in mature animals are mainly used for repairing and replacing cells (such as skin or blood cells).
• Sperm cells are specialised for reproduction.

  1. function is to get the male dna to the female dna
  2. has a long tail and streamlined head to help it swim to the egg.
  3. there are lots of mitochondria in the cell to provide the energy needed.
  4. also carries enzymes in its head to digest through the egg cell membrane.
• Nerve cells are specialised for rapid signalling

  1. function is to carry electrical signals from one part of the body to another.
  2. these cells are long (to cover more distance) and have branched connections at their ends to connect other nerve cells and form a network throughout the body.
• Muscle cells are specialised for contraction.

  1. function of a muscle cell is to contract quickly.
  2. these cells are long (so they have space to contract) and contain lots of mitochondria to generate energy needed for contraction.
• Root hair cells are specialised for absorbing water and minerals.

  1. root hair cells are on the surface of plant roots which grow into long “hairs” that stick out into the soil.
  2. this gives the plant a big surface are for absorbing water and mineral ions from the soil.
• Phloem and xylem cells are specialised for transporting substances.

  1. phloem and xylem cells form tubes which transport substances such as food and water around the plant.
  2. to form the tubes, the cells are long and joined end to end.
  3. xylem cells are hollow in the centre and phloem cells have very few su cellular structures so stuff can flow through them.